Package-binding machine with improved gripping means

ABSTRACT

A package-binding machine feeds a loop of binding material about a package and overlaps the ends of the material. A stop limits movement of the free end of the material and causes the stopped material to press against a concave guide surface, thereby closing an air opening which is located in that concave surface. Closing the air opening actuates a fluid cylinder which in turn actuates the gripping mechanism to hold the free end of the material against withdrawal when the loop is tightened about the package.

I United States Patent [111 [72] Inventor Pieter Arnolus Van de Bilt [56] References Cited A l N zggyf UNITED STATES PATENTS O. l 221 f; %221969 3,183,824 5/1965 Cook 100 4 Patented June 29, 1971 Primary Examiner- Billy J. Wilhite [73] Assignee N. V. Metaverpa Attorney-Young and Thompson [32] Priority Oct. 29, 1968 [3 3] Netherlands [3|] 68.15438 ABSTRACT: A package-binding machine feeds a loop of [54] MACHNE WITH IMPROVED binding material about a package and overlaps the ends of the material. A stop limits movement of the free end of the materil Chum 3 Drawing al and causes the stopped material to press against a concave [52] US. Cl 100/4, guide surface, thereby closing an air opening which is located lO0/26 in that concave surface. Closing the air opening actuates a [51] Int. Cl B!) 13/04 fluid cylinder which in turn actuates the gripping mechanism [50] Field of Search /4, 26, to hold the free end of the material against withdrawal when 25 the loop is tightened about the package.

PATENIED Juuze l97l SHEET 1 OF 2 INVENTOR BY f 57% ATTORNEYS PATENTEflJunzslsn 3.589275 SHEET 2 UF 2 L G o o INVENTOR P/ETE/Q 4 mach- 647 BY W7 WXMW ATTORNEYS PACKAGE-BINDING MACHINE WITH IMPROVED GRIPPING MEANS The present invention relates to package-binding machines of the type in which a length of material is trained about a package so that portions of the material overlap, whereupon these overlapping portions are fastened together.

In the specification and claims to follow, the term material refers to any flexible elongated material of indeterminate length, which may be fed from a supply of the same. The present application will disclose the invention in connection with metallic material such as wire or strip, but it is also to be understood that material within the scope of the invention includes plastic strips and webs, foils and other sheet or filamentary materials useful in package binding.

Similarly, the term fastening" herein, with respect to the securement together of the overlapping portions of the material, includes a number of different operations. The operation for fastening metal wires or bands is ordinarily a twisting operation, but it will of course be understood that a number of other fastening operations are also contemplated, such as heat sealing in the case of plastic strip or foil.

Machines of this type are already known. For example, one such machine discloses a device in which the end of the material as it completes the loop and overlaps another length of the material closes an air bleed port, which causes the pressure in an air duct to rise thereby actuating mechanism for performing subsequent steps.

However, a device as in the previously mentioned machine has the disadvantage that there is a certain loss of bandmaterial, because the band has to be advanced farther than is necessary for providing enough material for the twist, in order to be able to close the leak opening. Moreover, as the dimensions of the band, such as the thickness, are not always exactly the same, and as the relatively moving parts wear, such devices do not always accurately function. Moreover, variations in the apparatus must be made, in order to accommodate different sizes of band.

It is also known to provide an arrangement in which the end of the material strikes a stop which operates a plunger; the plunger opening or closing an air bleed. However, a device of this type suffers from the disadvantage that the signal for the operation of the fastening apparatus is given before the material has entered the fastening apparatus. Such devices rely on the inertia of the material and the time delay between the signal and the operation of the fastening device, with the result that often there is not a second thickness of material in the fastening device when the fastening device operates, as for example when the material advances too slowly. Moreover, a thin foil such as a plastic foil or even a plastic band may not have enough edgewise momentum and may wrinkle or clog the machine.

Accordingly, it is an object of the present invention to provide package-binding machines, in which the operation of the device for holding the free end of the material against retraction is not dependent on close dimensioning of the parts or of the material.

It is also an object of the present invention to provide package-binding machines, in which the operations that take place after the material is fully advanced will reliably occur, at the same time that a minimum of material is used.

Briefly, these objects are achieved by providing a stop for the leading end of the material just after it has completed the loop, and by providing a concave guideway such that the stopped material is pressed against the concave surface of the guideway by the pressure of the oncoming material, and by positioning in that concave guide surface an air opening whose obturation by the stopped material actuates the mechanism that grips the material.

Other objects and features and advantages of the present invention will become apparent from a consideration of the following description, taken in connection with the accompanying drawings, in which:

FIG. 1 is a schematic side elevational view ofa machine according to the present invention;

FIG. 2 is an enlarged fragmentary cross-sectional view of a portion of the machine of the present invention, in the area of the circle shown in FIG. 1; and

FIG. 3 is a simplified fluid circuit diagram of the present invention.

Referring now to the drawing in greater detail, and first to FIG. 1; there is shown a guiding frame 1 to which binding material is fed by a reversible drive mechanism 2. When the material has passed entirely about the loop in frame 1, it passes through a gripping and fastening device 3 after traversing a corner 4 of the frame 1, and then strikes a stop 5. The driving mechanism 2 reverses and the material is tightened about the package 6, the gripping and fastening device 3 holding the free end of the material against return movement and fastening together the overlapping portions of the material, as by twisting, sealing, etc. As thus far described, the structure and operation of the device are entirely conventional and may be as shown in U.S. Pat. No. 3,183,824.

The novel subject matter of the present invention is perhaps best illustrated in FIG. 2, which shows the enlarged corner 4 in the area of the circle of FIG. 1. It will be seen that the free end of the length of material, which was initially fed in the direction of the horizontal arrow in FIG. 2, is represented by the vertical arrow in FIG. 2 as it enters the corner 4 and follows the broken line 10. In that corner 4, a guide member 12 presents a concave guide surface to the free end of the material, so that the material turns the corner but does not necessarily engage the member 12 during all of its movement about the corner. An air bleed port 20 (FIG. 3) supplies air from a source of air under pressure, to the corner 4, and directs it substantially radially with respect to the curve of guide member 12, and exhausts it through an opening 11. During movement of the material, the opening 11 will not be obturated and the flow of air therefrom will not be impeded. But when the free end of the material strikes the stop 5, then the edgewise pressure of the oncoming :material will cause the material to be pressed against the concave surface of guide member 12, thereby at least partially closing the opening 11 and causing the air pressure upstream of opening 11 to rise.

FIG. 3 shows what happens when the opening 11 is open or closed. In the position shown in FIG. 3, the opening 11 is open, and air is supplied thereto through the conduit 13, from a conduit 14 that communicates with a source of air under pressure (not shown). Opening 11 is downstream from a restriction 20, so that when opening III is not closed, the air pressure between opening 11 and restriction 20 will be quite low. The pressure in pilot port 16b of a slide valve 16 will also be quite low, so that the spool will stay in the position as shown in FIG. 3 and conduit 13 is connected with conduit 14 through conduits 17 and 18. The spool will be hold in this position by friction of the moving parts of slide valve 16, pilot port 16c being vented. The pressure in conduit 18 will be relatively high compared to the pressure in vented conduit 19, the conduit 18 communicating with the chamber 15 on one side of a control piston and the conduit 19 communicating with the chamber 15a on the other side of this control piston. The control piston will thus be maintained in the FIG. 3 position, and will not activate the fastening device.

But when stop 5 causes the material to press toward and close the opening 11, then the pressure in 13 rises, and also the pressure in pilot port 16b. The spool of valve 16 is pushed upwardly as seen in FIG. 3, so that conduit 17 is placed in communication with conduit 19 and conduit 18 is vented, as well as conduit 13. The chamber 15a will be pressurized, chamber 15 being vented, so that the piston is pushed to the left, which actuates the gripping device, and may also if desired actuate the reversing mechanism that retracts the material, and other controls of the apparatus. Details of these further controls are shown in the above-identified U.S. Pat. No. 3,l83,824, and need not be further described here.

After the joint by the material has been made, pilot port 160 will be pressurized momentarily by a pilot valve (not shown) actuated by the joining mechanism.

From a consideration of the foregoing disclosure, therefore, it will be evident that all of the initially recited objects of the present invention have been achieved.

Although the present invention has been described and illustrated in connection with a preferred embodiment, it is to be understood that modifications and variations may be resorted to without departing from the scope of the invention, as those skilled in this art will readily understand. Such modifications and variations are considered to be within the purview and scope of the appended claims.

What I claim is:

1. In a package-binding machine comprising means for guiding binding material about a looped path, means for supplying binding material to said looped path, and means for holding the free end of the binding material when the latter has reached the end of the looped path; the improvement comprising a dead stop for the free end of the material at the end of said path, a portion of said guide means presenting to the material a concavely curved guide surface, said concavely curved surface having an opening therethrough that is obturated after the free end of the material strikes said dead stop, conduit means for supplying gas under pressure to said opening, and means responsive to an increase in pressure in said conduit means upon obturation of the opening to actuate said holding means said concavely curved surface being spaced from said stop whereby when said free end of the binding material engages said stop said binding material is then caused to press toward and close said opening as said supplying means continues momentarily to feed said binding means. 

1. In a package-binding machine comprising means for guiding binding material about a looped path, means for supplying binding material to said looped path, and means for holding the free end of the binding material when the latter has reached the end of the looped path; the improvement comprising a dead stop for the free end of the material at the end of said path, a portion of said guide means presenting to the material a concavely curved guide surface, said concavely curved surface having an opening therethrough that is obturated after the free end of the material strikes said dead stop, conduit means for supplying gas under pressure to said opening, and means responsive to an increase in pressure in said conduit means upon obturation of the opening to actuate said holding means said concavely curved surface being spaced from said stop whereby when said free end of the binding material engages said stop said binding material is then caused to press toward and close said opening as said supplying means continues momentarily to feed said binding means. 